This application relates to a computer network and, more specifically, to a method and apparatus for implementing an electronic document delivery system where both documents and billing information are encrypted during transmission.
An electronic document delivery system transmits documents from a central depository to individual nodes or receiving computers. In some conventional document delivery systems, a user accesses a computer at the central depository, examines a list of available documents stored at the central depository, and requests that one or more of the documents be transmitted to him. In other conventional document delivery systems, a predetermined group of documents are sent from the central depository to the user and stored on the user""s system. The user is then free to examine documents in the predetermined group. Still other conventional electronic document delivery systems can be used to send only certain types of documents, such as text-only documents.
Some electronic document delivery systems transmit documents to the user in encrypted form. The encrypted documents are received at the receiving computer and stored in a memory. Thereafter, the documents are decrypted and the decrypted form of the documents are also stored in a memory. Such double storage of documents is wasteful of memory and storage space.
What is needed is an electronic document delivery system in which a user can determine which documents he wishes to receive and in which the user is charged only for those documents that he receives. It is also desirable to allow the user to designate which documents he wishes to receive without having to access a central computer to view a list of available documents. Furthermore, it is desirable that such a system use encryption for all critical information passing between the central computer and the receiving computer. It also is desirable to avoid having both an encrypted and a decrypted version of a document stored at the receiving computer, as this is wasteful of memory space.
The present invention overcomes the problems and disadvantages of the prior art by having a central computer (or xe2x80x9cbroadcast centerxe2x80x9d) periodically send a xe2x80x9ccatalogxe2x80x9d of available documents to a receiving computer. The user can then browse through the available documents without having to access the broadcast center. The documents are transmitted as packets, and the packets are decrypted as soon as they are received, eliminating the need to store both an encrypted and a decrypted version of the documents at the receiving computer. Moreover, the invention is not limited to text-only documents and can receive all types of documents, such as software, images, text, and full-motion video. The receiving computer periodically receives information allowing it to decrypt received documents and to encrypt billing information to be sent to the broadcast center.
A purpose of the present invention is to allow all forms of electronic documents to be distributed in a cost-effective manner using broadcast technology in a way that prevents access to a document without paying for it.
In accordance with the purpose of the invention, as embodied and broadly described herein, the invention resides in a document delivery system comprising:
a broadcast center that sends a document as a plurality of encrypted packets;
a communication link connected to the broadcast center for carrying the packets;
a receiving computer, connected to the communication link, and including a memory and a broadcast receiver, wherein the broadcast receiver decrypts each packet as it is received and stores only the decrypted packets in the memory.
In further accordance with the purpose of the invention, as embodied and broadly described herein, the invention resides in a document delivery system in a network, comprising:
a broadcast center that sends a catalog containing a list of documents to be sent by the broadcast center;
a communication link connected to the broadcast center for carrying the catalog;
a receiving computer, connected to the communication link, and including a memory and a file browser, wherein the file browser receives the catalog and stores the catalog in the memory, displays the stored catalog, and receives user input indicating a document in the catalog.
In further accordance with the purpose of the invention, as embodied and broadly described herein, the invention resides in a method for document delivery in a network system, comprising:
the steps of sending, by a broadcast center in the network, a document as a plurality of encrypted packets;
connecting a communication link to the broadcast center;
decrypting a received packet in a receiving computer connected to the communication link, the receiving computer including a memory and a broadcast receiver, wherein the broadcast receiver performs the decrypting step on the packet as it is received and stores only the decrypted packet in the memory;
sending, by the broadcast center, account information including key seeds to a security engine in the receiving computer; and
generating, by the security engine, keys used by the broadcast receiver to decrypt the received packets in accordance with a one-way hashing method based on a document ID of the sent document and one of the key seeds.
It is understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.